The frame of a snowmobile typically includes a suspension module in a front portion of the frame for connecting a front suspension assembly between the skis and the frame, a motor module connected at the rear of the suspension module for receiving the motor of the snowmobile, and a tunnel connected at the rear of the motor module for connecting an endless track to the frame.
In some snowmobiles, the front suspension assembly is only connected to the suspension module, which is common when the front suspension assembly includes upper and lower suspension arms on both left and right sides. Such a construction is disclosed in U.S. Pat. No. 7,451,846 B2 for instance.
To withstand the forces encountered under normal operating conditions, the suspension module, the motor module and the tunnel and their respective parts are connected together using a plurality of fasteners and/or welds that adds significantly to the overall weight of the snowmobile. The manufacturing costs and complexity of the frame also increase as the number of fasteners and/or welds goes up.
Other components, such as cross members extending across the suspension module and/or the motor module, are sometimes provided to allow the suspension module and/or the motor module to withstand the forces applied to the frame by the suspension assemblies when the snowmobile travels through snow or when the skis impact the ground or other objects. These additional components further increase the weight of the snowmobile, its complexity, and its manufacturing costs.
Therefore, there is a desire for a frame and suspension assemblies for a snowmobile that address at least some of the inconveniences of the prior art.